One type of rotor aircraft has a rotor, at least one propeller, and wings. The rotor provides most of the lift during short or vertical takeoffs, slow speed flight, and landings, the wings provide most of the lift during cruise conditions. During cruise conditions, the rotor preferably free-wheels at a relatively slow speed. The rotor may be completely undriven in flight, or it may be driven for hovering. For take-offs with the undriven type, the pilot spins the rotor to a high speed while still on the ground. At liftoff, the rotor disengages from the engine, and the inertia of the rotor provides lift for a take-off. The propeller propels the aircraft forward to increase lift provided by the wings.
In the aircraft of the type described as well as the helicopters in general, both the cyclic pitch and the collective pitch are controlled. For collective pitch, with a two-bladed rotor, each blade twists about its feathering axis in opposite directions. Cyclic pitch refers to tilting of the plane of rotation in fore and aft directions as well as from one lateral side to the other. Various control mechanisms are employed to provide the cyclic and collective pitch adjustments. The control mechanisms extend alongside the mast, creating a fairly large mast and masthead assembly, which create drag during high speed flight.
Typically, helicopters do not utilize fairings around the mast or the masthead to reduce drag. The gyroplane described in U.S. Pat. No. 5,853,145 discloses a spinner fairing that fits around the masthead. The blades have cuffs that will twist relative to the spinner fairing to change the collective pitch. That patent also discloses a fairing around the mast.